The present invention relates to a driving device for use in an actuating drive in vehicles.
Actuating drives are increasingly being installed in luxury vehicles for various convenience functions. These drives have the task of replacing manual activation or operation with an automated actuating function. Recently, the proposal has been made to replace the manual movement of the gearing shift lever of an automatic transmission by such an actuating function. Another proposal is for the engine hood to be moved by an actuating device. The actuating devices that are suitable for such applications must generate considerable forces and must function very reliably. This requirement can be fulfilled with an electric motor that is followed by a speed reduction gear. However, in case of a power failure in the car""s electrical system, there still has to be a sufficient supply of energy to ensure minimum functionality. Moreover, a locking in certain positions is required.
Conventional driving devices cannot achieve these objectives.
The present invention provides a sturdy, simple driving device adapted to generate high actuating forces and which allows locking in predefined positions as well as quick and reliable unlocking.
The driving device according to the invention comprises a rotatable drive disc that is coupled to a motor. Arranged coaxially the drive disc is a locking disc that can be rotated to a limited extent relative to the drive disc. On its outer circumference, the locking disc has detent teeth. A pawl is pivotally mounted on a stationary axis to interact with the detent teeth. The drive disc has a cam that can be engaged by the pawl. On relative rotation of the drive disc and the locking disc, the pawl is lifted out of the detent teeth. Preferably, the drive disc is provided with a recess on its outer circumference. The outer circumference of the drive disc extends beyond the tips of the detent teeth. The bottom of the recess has approximately the same depth as that of the gaps between the detent teeth. Together with the outer circumference of the drive disc, the recess forms a cam on which the tip of the pawl slides.